Sketch of the great Geological Features of the Valley of Connecticut River, at Charlestown, New-Hampshire, and Remarks on some Crystals found in the Slate-rock scattered in that region; with specimens.

The valley of the Connecticut river, in its widest extent, may be said to be included between the summits of the Green Mountains of Vermont on the west, and those of the granite ridge, forming the height of land between it and the valley of the Merrimac, on the east. From the edges of the proper valley in which its waters flow, there is a continual though broken rise to these great boundaries, from whose sides flow the tributary streams of the river. The immediate valley is bounded by a steep ridge of hills on either side, between the feet of which and the river spreads an extent of fertile meadow; the deposit of the river, through which it winds its way, alternately approaching to and receding from these ranges of hills. The nucleus and substance of these hills in Charlestown, consists of strata of argillaceous slate, upturned nearly perpendicularly, the direction of the strata being nearly north and south, and the dip a little to the south of east. On the east side, passing over the summit of this first ridge, there is a slight valley, beyond which rises a ridge of granitic structure, seeming as if forced up through the chasm made by the depression of the eastern edge of the slate strata forming the first ridge, and holding them in place by its pressure on the inverted edge and sloping surface. Somewhat the same arrangement is to be found on the western side. The following is a sketch:

dd. Earth and coarse gravel forming the outer surface of the hills, in many places stratified, and resembling the deposits in the bed of a river.

e e. Meadows or interval land, consisting of fine silt.

G. River.

g. Plain of fine yellow sand, with a slight covering of vegetable mould, upon

which stands

f. The village of Charlestown.

The arrangement is not, however, altogether so simple as is represented in this sketch. The granite is often intermixed with beds of gneiss, many of them upturned like the strata of slate, and running parallel to them. These, as well as the slate, are seamed with veins of quartz, and sometimes of calcareous spar; and there are all gradations of slaty structure, from gneiss to argillaceous slate. In some places the slate is wanting, and the granite approaches close to the river, and even extends into it. On the Vermont side, beds of limestone occur occasionally be. tween the slate and the granitic rocks.

The soil of the hills, in the eastern part of Charlestown, abounds in fragments of slate, of a coarse texture, with numerous specks of black mica, and sometimes with small garnets, seemingly one of the varieties between argillaceous and mica slate. These fragments are of all sizes-from a mere pebble to the weight of many tons; some much worn, and others rough and angular, and with considerable dif ference in fineness of texture. They are all characterized, however, by the presence of numerous crystals, of a curious character, which form the more immediate objects of this paper, and of which I have the pleasure to send the National Institution a number of specimens; an end of each of which I have cut and slightly polished, for the purpose of showing more readily the structure.

These crystals have been variously denominated by different persons who have scen them, though no one appears to have given any careful description of them. One of the first persons who mentioned them to me, when I came into this part of the country to live, spoke of them as being crystals of staurotide; another after. wards called them macle, (and they are so termed in Cleveland's Mineralogy,) while Dr. Jackson, in the last report of his geological survey of New-Hampshire, speaks of them as macle, or (apparently as synonymous) hemitropic andalusite. They are certainly of considerable variety of structure, under a general similarity of configuration; and, while agreeing exactly with none of the minerals described under the foregoing names, have yet points of resemblance with each.

Staurotide, or granatite, as called by some, belongs to the garnet family, and macle and andalusite are of the feld-spar family, if macle be, as I presume, the same as chiastolite, according to the nomenclature of Jameson. His description of the mineral, to which he gives this name, is, as far as my recollection serves, almost precisely the same as that which Cleveland gives of macle.

The staurotide consists of two six-sided prisms, intersecting each other either at right angles or obliquely. The crystals in question are sometimes found in this form; and two of the specimens I send herewith, afford instances of it—one being an intersection nearly at right angles, and the other an oblique intersection, at about forty-five degrees. The generality of the crystals are, however, single, consisting of four-sided prisms, the bases of which are either rhomboids or rhombs. In the most perfect crystals, the latter shape is the prevalent one, and the figure is often very exact, the angles being extremely well defined. They have also a natural cleavage through the shorter diagonal of the rhomb, by which they are divided into two triangular prisms. Now Hauy shows that the primitive form of granatite is a quadrangular prism, the bases of which are rhombs, with a similar cleavage through the shorter diagonal of the base. The angles of the rhombs he makes to be about 130° and 50°, which agrees with the measurement of some of the most perfect of these crystals.

Some of them also agree with staurotide in other external characters, as the dark, reddish, brown color, the internal glimmering lustre between vitreous and resinous, in the general character of the fracture, in opacity, with occasional translucency, in hardness, brittleness, and infusibility. Yet still the specimens, in which these last characters are best marked, are precisely those which I have always found single, with rhombic or rhomboidal bases, and not intersecting each other. Those so intersecting have a different set of characters, apparently belonging more to the description of macle or chiastolite, yet not precisely agreeing with that,

Macle or chiastolite is described as being always crystallized in nearly rectangular four-sided prisms. When, however, the end of the prism is carefully examined, there will be perceived in it a blackish prism enclosed in the larger one, which is of a greyish, yellowish, or reddish white color. From each angle of the central prism a blackish line passes to the corresponding angle of the outer prism; and in each of these external angles there is commonly a small prismatic space, filled with the same black matter as that of which the central prism is composed, which is a dark clay slate, the same as the rock in which the crystal is imbedded.

As was before observed, Cleveland's description agrees with this, though, in conjunction with a figure corresponding to this description, he gives, as another variety, I think, a figure of a crystal with a rhombic base, the marking of which agrees very well with some of my specimens. I have never found any of these crystals rectangular, and but few approaching to that shape.

In the most perfect specimens, the whole rhomboidal crystal seems to be enveloped in a uniform coat of black, slaty matter, of a very fine grain, and easily admitting of considerable polish. When a cross section is made, (and it usually breaks in these specimens pretty smoothly,) and the surface ground down and polished, it will be seen that this thin black casing encloses a substance of a reddish yellow color, of glistening and somewhat foliaceous or sparry appearance, sometimes opaque, sometimes slightly translucent. This yellowish substance encloses a smaller hollow prism, of the same blackish matter, marked merely by a thin black line, and within it is contained the same reddish yellow matter, as filled the space between it and the outer coating; giving, in fact, the appearance of a small prismatic crystal, of yellowish matter, with a blackish coat inserted the centre of a larger crystal, of the same color, while small black lines pass from the angles of the inner case of black matter, to the corresponding angles of the outer. These black lines are very feint and delicate in the transverse diagonal of the crystal; thicker and more strongly marked in the longitudinal diameter; spreading a little as they approach the outer casing, so as to give the idea of being formed by a duplicature of that investment. In one or two crystals, indeed, this formation is distinctly marked.

In other crystals, less perfect, the bases are more generally rhomboids than rhombs. The outer black case is thicker, the yellowish contained matter less regular in its figure, (the angles being rounded off,) and, instead of an inner crystal resembling the outer, it is divided, by transverse diagonals of the black matter, into four portions. In some specimens these are very small, appearing on the section merely like dots, while the bulk of the crystal is composed of the blackish coat, which in these is rather grey than black. In other instances there is no regular figure to the contained matter, but it is dispersed through a black crystal, in irregu. lar patches, giving to the section a mottled appearance.

Although the disposition of the separate parts differs from the description, I have looked upon these two varieties as macle, but of a different variety from that commonly described. Yet it is among the second variety that I have found very good specimens of the intersection of crystals forming a cross.

In a third variety, there is no yellowish contained matter to be distinguished. The crystals consist wholly of blackish or grayish matter, sometimes with and

sometimes without a central spot corresponding with the shape of the crystal, of a different tint or texture from the rest. One or two of these that I send, have a reddish tinge in the gray, and I have conjectured that some more strongly tinged varieties of this kind may have induced Dr. Jackson to speak of them as andalusite; to which, otherwise, I have seen no resemblance in any crystals I have examined. Andalusite is usually hard enough to make a slight scratch upon quartz; while these grayish crystals may be cut or scraped with the point of a knife. This variety also affords instances of intersection.

As a fourth variety, I have ranked those described as resembling granatite in external characters, other than the hexagonal shape and crossing. In some of these, while the texture of the crystal seems the same, the insertion of the internal crystal, and the connecting lines of the angles, are distinctly marked by a light furrowed line, as of a joining. Some variety of this kind may be that of which Dr. Jackson speaks. He obtained his specimens from a locality several miles distant from me, and which I have never examined.

SPECIMENS.

In Package No. 1.-These are specimens of the most perfect form, having the inner crystal distinctly marked, with the diagonal joinings, and the appearance of duplicature of the outer investment to form the longitudinal diagonal. One of the specimens is triangular, being half of a crystal divided in its natural cleavage through the transverse diameter. Another is divided obliquely lengthwise, and two black lines may be observed traversing the crystal diagonally lengthwise.

Package No. 2.-This contains specimens of those described as the second variety, from the perfect form of those in No. 1, to a more central spot of the yel lowish matter, and two handsome specimens of the mottled kind. One of these specimens, with a central dot, is an imperfect six-sided prism, and is half of one of the crystals of a stauroidean formation. The remainder of the cross accom. panies this package.

Package No. 3.-Specimens of the gray and blackish variety, without any enclosed yellowish matter, but one or two of them with a darker nucleus, similar in shape to the external crystal. One of the gray crystals is an instance of an oblique intersection. This specimen is split longitudinally, and shows one crystal passing through the other.

Package No. 4.-Specimens of the dark reddish, brown variety, very hard, brittle, and difficult to be detached from the matrix. One of them has a perfect formation; in the others it is not to be discovered.

Quere. Are not these last crystals radically distinct from the others, and even from the perfectly shaped one with them?

All of the crystals that I have seen, have been found in the detached masses spoken of. I have never met with them in any ledge, though others have told me that they have found them so. I have fancied, from my own observation, that they mistook the projection of some huge half-buried fragment for the outcropping of strata, as they were persons of little experience in such researches.

FROM RICHARD RUSH: ON THE SMITHSON BEQUEST.
SYDENHAM, NEAR Philadelphia, March 4, 1842.

FRANCIS MARKOE, ESQ.,

Corresponding Secretary, National Institution.

DEAR SIR: I have to thank you for the "Bulletin of the Proceedings of the National Institution for the Promotion of Science," that you were so good as to send me; and although I am late in doing so, my thanks are not the less sincere. I have read it with great interest, and think that no one could read it without perceiving the advantages of such an institution. During the short period that it has been in operation, the indications are ample, both in the diversified objects which it proposes to itself, and in the communications addressed to it, that it will be likely to prove metropolitan in character and usefulness, as it is in situation.

But what impels me, on this occasion, to something beyond a mere formal though thankful acknowledgment for the Bulletin, is the desire to notice a passage in two communications it contains-one from Mr. Duponceau, of Philadelphia, and the other from Mr. Maxcy, our Chargé d'Affaires at Brussels, relative to the Smithsonian legacy.

Both these correspondents of the Institution, the former long and favorably known to philosophy and science, the latter an enlightened and patriotic American, looking at his country from abroad, have, without concert, united in the opinion that it was such an institution as yours that Mr. Smithson must have meant in making the munificent provision in his will for establishing one at Washington, and in the wish that Congress might take it as a basis in fulfilment of his intention.

I cannot restrain the impulse that would add my humble though not less earnest opinion and wish to theirs.

If it be scarcely a dispute that individual zeal and exertion can do more towards striking out useful projects for mankind than Governments, it would not be easy to imagine a case in which this truth could be more applicable than to the Smithson trust.

This great and beneficent trust remains wholly unexecuted by the hands of Government, though to those hands solemnly confided, and as solemnly accepted. Would this have been the case had it been confided to individual hands? A negative reply may be safely given.

A native of France, long a citizen of the United States, dies in the midst of us. He leaves two millions of dollars to found a college for the education of orphans, in a city of one of our States, confiding the management of his bounty to legisla. tive and municipal authority. Already ten years have elapsed, and the philanthropic intentions of the munificent donor remain a dead letter. I allude to the Girard trust.

A generous and enlightened Briton dies abroad. He leaves a hundred thousand pounds sterling to the United States, to found, at Washington, an Institution "FOR

THE INCREAse and diffuSION OF KNOWLEDGE AMONG MEN."

What a beautiful simplicity in his words! How comprehensive they are! How boundless in their intended benefits! Yet we are now approaching the fourth summer since the money was delivered to the United States, as the high trustee of this great duty, and the intentions of this donor, too, are still a dead letter.